Extraction des multiplications hors de tweakey.c

De  façon à  ce  que  d'autres versions  puissent  réutiliser l'un  ou
l'autre.

1 files changed, 114 insertions, 0 deletions

diff --git a/src/ref/multiplications.h b/src/ref/multiplications.h
new file mode 100644
index 0000000..32327f2
--- /dev/null
+++ b/src/ref/multiplications.h
@@ -0,0 +1,114 @@
+/*
+Implementation of the Lilliput-AE tweakable block cipher.
+
+Authors, hereby denoted as "the implementer":
+    Kévin Le Gouguec,
+    2019.
+
+For more information, feedback or questions, refer to our website:
+https://paclido.fr/lilliput-ae
+
+To the extent possible under law, the implementer has waived all copyright
+and related or neighboring rights to the source code in this file.
+http://creativecommons.org/publicdomain/zero/1.0/
+
+---
+
+This file implements the alpha-multiplications used in Lilliput-TBC's
+tweakey schedule, where each matrix M and M_R to the power n are
+implemented in distinct functions with shifts and XORs.
+*/
+
+#ifndef MULTIPLICATIONS_H
+#define MULTIPLICATIONS_H
+
+#include <stdint.h>
+
+#include "constants.h"
+
+static void _multiply_M(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
+{
+    y[7] = x[6];
+    y[6] = x[5];
+    y[5] = x[5]<<3 ^ x[4];
+    y[4] = x[4]>>3 ^ x[3];
+    y[3] = x[2];
+    y[2] = x[6]<<2 ^ x[1];
+    y[1] = x[0];
+    y[0] = x[7];
+}
+
+static void _multiply_M2(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
+{
+    uint8_t x_M_5 = x[5]<<3 ^ x[4];
+    uint8_t x_M_4 = x[4]>>3 ^ x[3];
+
+    y[7] = x[5];
+    y[6] = x_M_5;
+    y[5] = x_M_5<<3 ^ x_M_4;
+    y[4] = x_M_4>>3 ^ x[2];
+    y[3] = x[6]<<2  ^ x[1];
+    y[2] = x[5]<<2  ^ x[0];
+    y[1] = x[7];
+    y[0] = x[6];
+}
+
+static void _multiply_M3(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
+{
+    uint8_t x_M_5  = x[5]<<3  ^ x[4];
+    uint8_t x_M_4  = x[4]>>3  ^ x[3];
+    uint8_t x_M2_5 = x_M_5<<3 ^ x_M_4;
+    uint8_t x_M2_4 = x_M_4>>3 ^ x[2];
+
+    y[7] = x_M_5;
+    y[6] = x_M2_5;
+    y[5] = x_M2_5<<3 ^ x_M2_4;
+    y[4] = x_M2_4>>3 ^ x[6]<<2 ^ x[1];
+    y[3] = x[5]<<2   ^ x[0];
+    y[2] = x_M_5<<2  ^ x[7];
+    y[1] = x[6];
+    y[0] = x[5];
+}
+
+static void _multiply_MR(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
+{
+    y[0] = x[1];
+    y[1] = x[2];
+    y[2] = x[3]    ^ x[4]>>3;
+    y[3] = x[4];
+    y[4] = x[5]    ^ x[6]<<3;
+    y[5] = x[3]<<2 ^ x[6];
+    y[6] = x[7];
+    y[7] = x[0];
+}
+
+static void _multiply_MR2(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
+{
+    uint8_t x_MR_4 = x[5] ^ x[6]<<3;
+
+    y[0] = x[2];
+    y[1] = x[3]    ^ x[4]>>3;
+    y[2] = x[4]    ^ x_MR_4>>3;
+    y[3] = x_MR_4;
+    y[4] = x[3]<<2 ^ x[6]      ^ x[7]<<3;
+    y[5] = x[4]<<2 ^ x[7];
+    y[6] = x[0];
+    y[7] = x[1];
+}
+
+static void _multiply_MR3(const uint8_t x[LANE_BYTES], uint8_t y[LANE_BYTES])
+{
+    uint8_t x_MR_4  = x[5]    ^ x[6]<<3;
+    uint8_t x_MR2_4 = x[3]<<2 ^ x[6]    ^ x[7]<<3;
+
+    y[0] = x[3]      ^ x[4]>>3;
+    y[1] = x[4]      ^ x_MR_4>>3;
+    y[2] = x_MR_4    ^ x_MR2_4>>3;
+    y[3] = x_MR2_4;
+    y[4] = x[0]<<3   ^ x[4]<<2   ^ x[7];
+    y[5] = x_MR_4<<2 ^ x[0];
+    y[6] = x[1];
+    y[7] = x[2];
+}
+
+#endif /* MULTIPLICATIONS_H */